Power transformers, capacitors, breakers and switches are electrical components extensively used by electrical utilities. With the notable exception of dry or gas-filled transformers, these electrical components typically contain insulating oil. Depending on the size of the electrical system, some of the transformers may contain several tens of thousand of liters of oil. As components of electrical transmission and distribution systems, these electrical components may be located within the limits of a transformer station, installed in remote locations, or located within a user's site or facility.
Despite rigorous design and operational maintenance programs, failures of these electrical components occur. Catastrophic failures may result in the spill of thousands of liters of oil with damaging consequences for the environment. Depending of the type of failure and the specific circumstances, the oil spill may be accompanied by a fire of the oil and possibly the equipment. Even if an electrical component does not catastrophically fail during its operational life, energy overloading and environmental condition cycles often cause chronic oil leaks in the electrical component. Because of the cost and need to maintain a reliable electrical supply for users, these leaks are rarely repaired. Thus, chronic leaks may cause prolonged damage to the environment. The sudden, large volume of oil following a failure of an electrical component or the small, but continuous stream of oil from a chronic leak may find its way into waterways or into the water table causing ground water contamination.
Environmental regulations, concerns of environmental groups, the large and increasing costs of soil remediation, and internal environmental policies are among many factors driving many companies to seek new solutions to address oil spills and flawed current management practices for chronic oil leaks. However, the number of options available is limited and available technologies are typically cost prohibitive and/or fail to provide adequate protection.
A known method of containing oil spills or leaks from electrical components is to use a concrete containment area under and/or around the protected equipment. This containment area is usually built with a water/oil separator used to separate rainfall or snow melt water collected in the containment area from the oil that might have leaked or spilled from the equipment. A drawback of this approach is that it is capital cost intensive and requires significant maintenance efforts to maintain the oil containment system effective.
Another method is to use an impermeable membrane within a concrete containment area. The membrane is supported by a concrete curb or other wall system to create a containment area with a volume sufficient to collect some or all of the oil in the electrical equipment in the event of a catastrophic failure. This approach has a number of drawbacks that may make it unreliable and ineffective. Firstly, sunlight may affect the membrane's long-term durability, creating cracks and changing its original oil resistant characteristics. Secondly, rainfall and snow melt water may collect in the containment area creating a hazardous condition. Thirdly, difficulties in sealing the containment system around cables and other protuberances from the equipment may result in oil leaks and improper containment. Fourthly, the high temperature that would be created by an oil fire would destroy the protective membrane.
Thus, in view of the drawbacks of the prior art, there remains a need for a more cost-effective and reliable apparatus for the containment of oil spills and chronic oil leaks from oil containing equipment.